ath9k: Set default noise floor value for AR9287

The default noise floor was never initialized for
AR9287.This patch helps in reporting the correct
RSSI for this version of chipset.

Signed-off-by: Vivek Natarajan <vnatarajan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/calib.c b/drivers/net/wireless/ath/ath9k/calib.c
index 3234995..439f2c7 100644
--- a/drivers/net/wireless/ath/ath9k/calib.c
+++ b/drivers/net/wireless/ath/ath9k/calib.c
@@ -697,6 +697,8 @@
 		noise_floor = AR_PHY_CCA_MAX_AR9280_GOOD_VALUE;
 	else if (AR_SREV_9285(ah))
 		noise_floor = AR_PHY_CCA_MAX_AR9285_GOOD_VALUE;
+	else if (AR_SREV_9287(ah))
+		noise_floor = AR_PHY_CCA_MAX_AR9287_GOOD_VALUE;
 	else
 		noise_floor = AR_PHY_CCA_MAX_AR5416_GOOD_VALUE;